Fluorinated oil- and water-repellent and dry soil resistant polymers

ABSTRACT

FLUORINATED OIL- AND WATER-REPELLANT AND DRY SOIL RESISTANT POLYMERS CONTAINING UNITS DERIVED FROM MONOMERS HAVING THE STRUCTURE R1CH2CH2O2CCH=CH2 WHEREIN R1 IS A PERFLUOROALKYL GROUP OF ABOUT 4 THROUGH 14 CARBON ATOMS, AND METHYL ACRYLATE OR ETHYL ACRYLATE, AND OPTIONALLY CONTAINING SMALL AMOUNTS OF UNITS DERIVED FROM MONOMERS SELECTED FRM CH2=CRCONHCH2OH, CH=CRCO2CH2CH2OH AND MIXTURES THEREOF WHEREIN R IS H OR CH3.

United States Patent O 3,645,989 FLUORINATED OIL- AND WATER-REPELLENT AND DRY SOIL RESISTANT POLYMERS Thomas King Tandy, Jr., Newark, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del. No Drawing. Filed Jan. 29, 1970, Ser. No. 6,961 Int. Cl. C08f 15/24, 15/40 US. Cl. 26080.73 11 Claims ABSTRACT OF THE DISCLOSURE Fluorinated oiland water-repellent and dry soil resistant polymers containing units derived from monomers having the structure R CH CH O CCH CH wherein R is a perfiu'oroalkyl group of about 4 through 14 carbon atoms, and methyl acrylate or ethyl acrylate, and optionally containing small amounts of units derived from monomers selected from CHFCRCONHCH OH, CH=CRCO CH CH OH and mixtures thereof wherein R is H or CH BACKGROUND OF THE INVENTION (l) Field of the invention The invention relates to novel fluorinated polymers containing R CH CH O CCH CH and methyl acrylate or ethyl acrylate wherein R is a perfluoroalkyl group of from about 4-14 carbon atoms, which are useful in treating textile fabrics to render said fabrics oiland water repellent and dry soil resistant.

(2) Description of the prior art While a variety of art-known fluorine containing polymeric materials presently used in the treatment of textile fabrics are capable of effecting oil and water repellency in said fabrics, there are still several extant problems in the area of repellency which are not overcome by knownoiland water-repellent fluorinated polymers.

One such problem is that most, if not all, of the presently known fiuorinated oiland water-repellent polymer systems require a rather high temperature cure after application to develop oil repellency. This is completely incompatible with most permanent press systems. The resins used in such systems also require rather high temperature cures but such cure cannot be applied until after the textile is converted into the final form of the garment and the desired creases applied. Textiles treated with permanent press resins and presently available oiland water-repellents are therefore not oil-repellent until the garment is complete. A large amount of such textile is soiled by oils and greases during garment manufacture without any benefit being gained from the oiland waterrepellent. The textile and garment manufacturers would,

of course, like to have their permanent press treated fabric oil-repellent during garment manufacture but presently they cannot.

A second problem is that many of these fiuorinated polymer-treated textiles lose their oil and water repellency after laundering when the textile is dried in air at ambient temperatures. The repellency can in large part be restored by heating as, for example, during pressing or during drying in a heated drier. This lack of repellency after the so-called home wash-air dry laundering has greatly affected usefulness of the fluorinated oiland water-repellents in the permanent press garment market, for example, where the entire purpose of the permanent press treatment is to obviate the necessity for pressing or heated drying. A second facet of this problem is, of course, that the laundered fabrics lack any protection provided by oil repellency in particular bet-ween laundering and the pressing or heated drying which otherwise restores repellency. The polymers of this invention continue to impart oil and water repellency to textiles after laundering and air drying.

Another problem is that fluorinated polymers which provide repellency to oils and water (liquids) do not by necessity have any repellency for dry-soils, i.e., particulate matter. Such particulate matter usually soils a fabric by being rubbed or ground into the fabric, for example, between and among the individual threads. Removal of such dry-soil requires the laundering medium to suspend the particle and float it away from the fibers of the fabric. If the fabric repels water, of course, it is more difiicult to remove the particulate matter.

Novel fluorinated polymers have now been discovered which, when used in treating textile fabrics, display the desired properties and qualities such as imparting oil repellency prior to curing maintaining this repellency even after laundering or washing and also imparting to the treated textile fabric a resistance to dry soiling, thus overcoming some of the outstanding problems in the area of oil and water repellency and dry soil resistance which exist for garment manufacturers and the like.

SUMMARY OF THE INVENTION The present invention is directed to oiland waterrepellent and dry soil resistant polymers. These polymers contain about 60 to parts of units derived from monomers having the structure R CH CH O CCH=C H where R, is a perfluoroalkyl group of about C and about 40 to 5 parts of units derived from methyl acrylate or ethyl acrylate monomers. The sum of these monomerderived units present in the polymer is parts.

It is also often desirable to add a monomer selected from units derived from CHFCRCONHCH OH CHFCRCOgCHgCHzOH and mixtures thereof, wherein R is H or CH The amount of units derived from these monomers which will be used may vary from 0 to 1 part per 100 parts of the other two monomers. These polymers preferably have an inherent viscosity as a 0.5% solution in trichlorotriiluoroethane at 30 C. of from 0.2 to 3.

DESCRIPTION OF THE INVENTION These new fluorinated polymers contain two essential ingredients. The first is a monomer having the structure R CH CH O CCH=CH wherein R, is a perfiuoroalkyl group of from about 4 to 14 carbons. From about 60 to 95 parts of units derived from such monomers must be present in the polymer.

In these monomers R CH CH O CCH=CH the periluoroalkyl group R is preferably a mixture of straight chain groups CF CF (CF where n is 4, 6, 8, 10 and 12 in the approximate weight ratio 35/30/18/8/3, the monomer having an average molecular weight of 508 moles wt. These are preferred since mixtures of these groups are commercially available, financially practical and give the best results. Branched or other straight chain perfiuoroalkyl groups may, however, also be utilized.

The second essential monomer in the present polymers is methyl acrylate or ethyl acrylate with methyl acrylate being preferred. From about 40 to 5 parts of units derived from such monomers must be present in the polymer.

The sum of the units derived from the first and second essential monomers present in the polymer is 100 parts.

It is often desirable though not essential to include in the polymers of this invention small amounts of units derived from certain monomers which can lead to greater durability to dry-cleaning and laundering. While satisfactory durability exists absent these monomers, a still more durable product may result when they are present. These monomers are chosen from N-hydroxyalkyl acrylamides of structure CH CRCONHCH OH, hydroxyalkyl acrylic esters of structure CH =CRCO CH CH OH and mixtures thereof, wherein R is H or CH The monomers which are used and are commercially available are N-methylol acrylamide, N-methylol methacrylarnide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and of these, N-methylol acrylamide and 2-hydroxyethyl methacrylate are preferred. About to 1 part of units derived from these optional monomers may be present per 100 parts of units derived from the two essential monomers.

The preferred polymers of this invention contain about 85-90 parts R CH CI-I O CCH=CH -10 parts methyl acrylate, 0.25 part N-methylol acrylamide and 0.25 part Z-hydroxyethyl methacrylate. The polymers of this invention must be emulsion polymers, that is, prepared by an emulsion polymerization technique. Emulsion polymerization, as used herein, means that the monomers are emulsified in water with a suitable emulsifying agent and are caused to polymerize with a water soluble initiator.

In preparing the polymers of this invention according to the usual emulsion polymerizataion techniques, it is preferable to control the molecular weight of the polymer by addition of small amounts of a chain transfer such as dodecylmercaptan. In general, from about 0.04% to 1.0%, based on total weight of monomers, is used. The polymers having lower molecular weight, i.e., those resulting when the amount of dodecylmercaptan is nearer 1.0%, generally have somewhat better soil resistance than the polymers of higher molecular weight, i.e., those resulting when the amount of dodecylmercaptan is nearer 0.04% or is entire- 1y absent.

[The emulsion polymerization is otherwise quite standard. The monomers are preemulsified in water using a suitable emulsifying agent, the initiator is added, polymerization is initiated by heating and heating is continued until polymerization is complete. Any emulsfying agent which does not interfere with polymerization may be used. Prefer-ably, cationic agents such as either the quaternary salts [RN(CH ]+X- or the acid salts [RN(CH -HX are used. In both cases R is a longer chain alkyl group, of from about 12 to carbons, and X is a water solubilizing cation such as halide ion, acetate ion, etc. Any water soluble initiator may be used; the water soluble azo compounds such as azobis(isobutyramidine)dihydrochloride are preferred.

It is generally preferable, if the most advantageous polymer properties are to be obtained, that the inherent viscosities of the polymers of this invention be from 0.2 to 3, when measured at C. as 0.5% solutions in trichlorotrifluoroethane. Inherent viscosity is determined by the formula 1 V V; 6 1D where V, is the inherent viscosity, C is the polymer concentration in grams per 100 ml. of solution, V is the viscosity of the solution, V is the viscosity of the solvent and In is the natural logarithm.

For use in oil and water-repellent formulation, the polymer emulsions obtained by the above procedures are usually used directly in the pad bath without isolation of the polymer.

The compositions are applied to the textile fabric preferably as an aqueous dispersion by brushing, dipping, spraying, padding, roll-coating or by any combination of these methods. For example, the prepared concentrated dispersion of polymer composition may be used as a pad bath by diluting it with water to a solids content of 0.1% to 10% by weight of the bath. The textile material is padded in this bath, and is then freed of excess liquid, usually by squeeze rolls, so that the dry pickup (weight of dry polymer on fiber) is between 0.1% and 10% by weight of the fiber. The treated material is then dried by heating, say in an oven at 135 to 172 C. until dry.

The dry fabric is oil and water repellent without further heating but such further heating may increase the degree of repellency somewhat. The textile material will retain repellency even after many launderings or drycleanings.

It is common practice to treat fabrics with several agents at the same time. These agents may include softeners, crease resistance agents, wetting agents, antistatic agents, resin finishes, soil release agents and the like. When used in the presence of such agents, concentrations of the polymers of this invention lower than those required when used may be required to obtain equivalent repellency. It is also common practice to add auxiliary water repellents to treating baths. In general, far more of the polymers of this invention are required to obtain maximum water repellency than maximum oil repellency. Commercially, it is cheaper to add only as much polymer as is required to obtain the desired oil repellency, then to add the far cheaper water repellents to bring up water repellency to the desired level.

More recently, another development has occurred in the textile trade, the permanent press treatment, as taught, for example, in US. Pat. 2,974,432. In this treatment, a permanent press resin such as noornN-onon 0: nocm-N- non described in US. Pat. 3,049,446 is coapplied along with the polymers of this invention. In some cases such resins are not cured, however, until the textile is fabricated into the finished article. It is important, therefore, that the textile is repellent, without anything more than drying, which occurs when using the polymers of this invention, as above indicated.

Suitable substrates for application of the polymers of this invention are fibers, yarns, fabrics and articles made of filaments, fibers or yarns derived from natural, modified natural or synthetic polymeric materials or from blends of these. Examples are cotton, silk, regenerated cellulose, nylon and like synthetic polyamides, fiber-forming linear polyesters, fiber-forming polyacrylonitrile and modified acrylonitrile polymers, cellulose nitrate, cellulose acetate, fiberglass and the like. These may be in many forms of knit and woven fabrics including sateen, poplin, broadcloth, jean cloth gabardine, upholstery materials as well as nonwoven fabrics and the like used to fabricate rainwear, work clothing, suiting, female apparel, renting, autobody tops, furniture upholstery, draperies and a variety of others.

EXAMPLES The following examples are intended to be merely illustrative of the invention and not in limitation thereof. Unless otherwise indicated, all quantities are by weight.

The fluorinated monomer in all cases had the structure CF CF (CF ),,CH CH O CCH=CH wherein n is 4, 6, 8, l0 and 12 in the weight ratio 35/30/18/8/3, average molecular weight 508, prepared by following the procedure of Example II of the Fasick and Reynolds US. Pat. 3,282,905, using the alcohols CF CF (CF CH CH OH and methyl acrylate. These alcohols were prepared by utilizing the procedure of Parsons, US. Pat. 3,234,294 to prepare CF CF (CF ),,I, the procedure of Haszeldine, J. Chem. Soc., 149, 2856 to prepare cr crgcrp cu cn r and the procedure of Day, US. Pat. 3,283,012 to pre pare the alcohols themselves. Alternatively, the esters may be prepared from the iodides CF CF (CF ),,CH CH I using the procedure of Fasick, US. Pat. 3,239,557.

EXAMPLE 1 Several polymers were prepared using the procedure below and having the compositions, monomer proportions and viscosities shown in Table I.

A 60% by weight monomer emulsion in water containing by weight C1248 alkyl trimethylammonium chloride was prepared by combining R CH CH O CCH CH2 methyl acrylate and water with high speed agitation. The mixture was then further agitated for ten minutes and diluted with water to 50% monomer concentration. The 50% emulsion was purged with nitrogen for one hour, then the desired amounts of N-methylolacrylamide (as a 60% aqueous solution) and 2-hydroxyethyl methacrylate were added along with a small amount of dodecylmercaptan (0.075 to 0.20%). The resulting emulsion was then further diluted to 25% concentration, heated to 65 C. under nitrogen and 2,2'-azobisisobutyroamidine dihydrochloride (about 0.07%) was added. The temperature was held for about four hours at 70 C. The resulting emulsion of polymer solids contained about 25% solids by weight. Inherent viscosities were determined as described previously in 1,1,2 trichloro-1,2,2-trifluoroethane as 0.5% solutions at 30 C.

Another group of polymers was prepared using 5% dimethyloctadecylamine acetate surfactant in the abovedescribed procedure. These polymers are also shown in Table I.

TABLE ship: percent OWF=percent bathx percent wet pickup/ 100. Several fabrics were padded with these baths, dried and cured for the indicated times at 171.1 C. (340 F.) (unless noted otherwise), The treated fabrics were tested for oil and water repellency, initially and after one or more launderings and dry-cleanings. Certain treated fabrics were also tested for dry-soil repellency as will be seen in Example 5.

Water repellencies of the treated fabrics were determined using Test Method 22-1952 of the American Association of Textile Chemists and Colorists. A rating of 100 denotes no water penetration or surface adhesion, a rating of 90 denotes slight random sticking or wetting and so on.

Oil repellency test comprises placing a drop of test solution carefully on the textile on a fiat horizontal surface. After three minutes, any penetration or wicking into the fabric is noted visually. To aid in the observation, the test solutions in some cases contained a small amount of oil-soluble blue dye to increase visibility. The nature of the test solutions is shown below; Nujol, of course, is a purified petroleum oil. Anything with a rating or five or greater is good or excellent, anything with a rating of one or over can be used for certain purposes. As an example, if a treated fabric repels the No. 1-6 solutions but not the number 7 solution, its rating is 6.

All polymers contain 0.25 part N-methylol acrylamide and 0.25 part Z-hydroxyethyl mcthacrylate Polymer No. parts Second monomer Methyl acrylate. do

Octyl acrylate. 1:..1 lllq/lethyl acrylate.

t "do 7 Octyl acrylate Parts s-n w coo Surfactant Percent A=hexadecy1trimethyl ammonium chloride; B=oetadecyldimethylamine acetate; C=octadecyltrimetl1yi ammonium chloride.

* Percent on weight of mixture.

Several of the above-prepared emulsions were diluted with water to contain sufiicient polymer to provide 6.21% CF CF (CF CH CH O CCH CH in polymerized form in the emulsion, i.e., all such emulsions then had equal fluorine content. Each of these emulsions was padded on various fabrics. Pad baths were prepared according to the formulations defined in Examples 2-4 and containing several polymers prepared in Example 1.

Home laundering tests were carried out in a Kenmore washer Model 600 loaded with a 4-1b. load, with 29 g. Tide, The wash is set at hot (12 min. cycle) and a warm rinse (12 min.). The total washing and rinsing time is minutes. In the home Washing air-dry test (HWAD), the spun-dry fabrics are dried at ambient temperatures. In the home washing tumble-dry test (HWTD), the spun-dry fabrics are dried at 156160 The bath concentrations were determined by the relation- 7 F. in a home drier with tumbling.

The dry-cleaning test consists of agitating the sample for 120 minutes in tetrachloroethylene containing 1.5% (weight/volume) of a commercial dry-cleaning detergent (R. R. Street Co., 886 Detergent), extraction with tetrachloroethylene, drying for three minutes at 66 C. in a drum and followed by a 15 second pressing at 149 C. on each side of the fabric.

Resisistance to dry soiling was tested by a method perfected by the Ford Motor Company. The procedure is as follows:

A sample, x 5 inches, of each tested fabric is prepared, A light reflectance reading is taken using the Colormaster Differential Colorimeter, Meeco Instrument Manufacturing and Engineering Equipment Corp., Warrington, Pa., using the rfilter which gives the highest refiectance reading. A 5 x 5 inch card stock template having 1 x 1 inch square hole in the center is then placed on the sample and 0.1 g. of synthetic soil is applied through a 40 mesh sieve. The sample, template and covering 96 x 100 thread white cotton cloth are then clamped to a 4 x 6 X inch urethane foam block and placed in a pilling tester (Custom Scientific Instruments, Inc., Arlington, N.J., catalog No. (TS-53041). A 2 x 2 x inch urethane foam block covered with the same cotton cloth is placed in the floating rack. The floating block is passed back and forth over the covered test sample for two minutes. The pilling tester machine requires modification to take the urethane foam blocks. Loose soil is then removed from the sample by holding a 50 psi. air nozzle on the fabric and moving it back and forth over the fabric once each in the warp and file directions. A reflectance reading is then taken in the soil area. The percent soiling is then determined by the equation percent so1l1ng= Where R is reflectance before soiling and R after soiling.

The synthetic soil was the so-called Cyanamide Soil and had the following composition:

The results obtained are shown in the tables of Examples 25 below.

EXAMPLE 2 A formulation was prepared as described above having the following composition: a

Formulation A.Permanent press Component: Percent OWF Permanent press resin 12.0. Catalyst 2.3. Stabilizer d 0.04. Polymer emulsion As indicated.

a "Permafresh183an aqueous emulsion of the dihydroxydimethylol ethylene urea described before.

0 27% aqueous zinc nitrate. 30% aqueous.

On weight of bath. B 6.21% aqueous emulsion of indicated polymer.

This formulation was then applied by padding to a /35 Polyester/ Cotton Poplin fabric and the results are shown in Table II below.

TABLE II.FORMULAT1ON A {Fabrie=65/35 polyester/cotton poplin; cure: 10 min, 171.1 0.]

Repellencies-3 minute dyed oils P t Initial HWAD a HWTD b 5 HWTD b 1 DC u 5 DC 11 ereen Polymer No. OWF Oil Water Oil Water Oil Water Oil Water Oil Water Oil Water 14 2. 5 5 4 70 4 70 4 50 4 70 5 50 5. 0 6 6 80 5 7 O 5 70 5 70 6 50 2. 5 5 70 2 70 4 70 3 70 4 70 4 50 5. 0 6 80 4 80 5 70 4 70 5 70 6 70 2. 5 5 70 2 70 4 70 3 50 3 70 4 50 5.0 6 80 4 8O 5 70 4 70 5 70 5 50 2.5 5 70 2 70 4 70 3 70 3 70 4 50 2.5 l 70 0 70 0 70 0 50 0 0 l 50 5.0 2 70 0 70 0 70 0 50 1 0 2 50 2. 5 5 80 2 70 3 70 2 50 4 50 4 50 5. 0 6 80 5 80 5 70 4 5O 5 70 5 50 2. 5 5 70 2 70 3 70 3 70 4 70 4 70 5. 0 6 80 3 80 5 70 4 70 4 70 5 50 2.5 5 70 2 70 4 70 3 70 4 70 4 70 5. 0 6 80 5 80 5 70 5 70 6 70 d 70 2.5 l. 70 0 50 0 70 0 50 6 50 1 0 5. O 3 80 1 70 1 70 1 50 2 70 2 50 2. 5 6 70 1 50 2 50 1 50 4 50 4 50 5. 0 6 70 i 50 4 70 2 50 5 50 4 5D 2. 5 5 70 2 70 3 2 2. 5 5 70 3 70 4 3 2. 5 5 70 2 70 2 2 2. 5 6 70 5 70 5 5 2. 5 5 70 5 50 5 5 2. 5 6 70 4 50 5 5 2. 5 3 70 1 70 2 2. 5 6 70 4 70 5 2. 5 5 70 4 50 4 0 D C dry-cleaning.

9 EXAMPLE 3 Formulation B.--Crease resistant finish EXAMPLE 5 The formulations of Examples 2-4 were used to pad various materials which were then tested for dry-soiling resistance. The results are shown in Table V below. It

5 Component: Percent OWF should :be noted that for purposes of comparision two a polymers were utilized in these formulations, I-15 wh1ch Crease resistant resin 2.0. catalystb 02 is within the scope of the invention and I-20 WhiCh 1s Isopropanol c 3.0. Acetic acid 5 TABLE V Stabilizer c 0.04.

e Percent soiling Polymer dispersion As indicated. Formw Percent a. 23 s Fabric lation OWF 1-15 1-20 b 27? aqueous zinc nitrate. :On veight of bath. B dqueous- Polyester C 116 5310 2.0 61.3 77.8 (CHgCHzOhH B 1.6 22.5 29.2 N 1 n mm 2.0 25.7 32.3 C1EH37N -HCl 1 0 1.6 20.9 25.3 (CH CH 0) 1. i2 22 2 z y 20 B 74.2 PHI-15' Cotton poplin "{C g; 22:2 3kg 9 i 2.0 73, 9 82.9 e 6.21% aqueous emulsion of indicated polymer. A L6 7 5&9 This formulation was then applied by padding to Cotton 65/35 polyester cotton f-g i=2 gig Poplin and nylon fabrics and the results are shown in 25 C i 2.0 60.8 68:2 Table HI below.

TABLE III.FORMULATION B [Cure 117 C. for 3 minutes] Repellencies-B minute dyed oils Initial HWTD DC 5 DO Polymer Percent Example No. Fabric OWF 011 Water Oil Water Oil Water 011 Water L1 {Cotton poplin 2. 0 2 1 0 2 50 2 50 Nylon 2.0 3 70 2 70 3 70 2 70 2.0 2 so 1 2 50 2 50 2.0 2 7o 2 a 10 a 70 2.0 2 70 2 0 2 50 2 50 2.0 2 70 2 70 a 70 a 70 2.0 2 50 2 50 2 50 2 50 2.0 3 7o 2 50 a 70 4 70 2.0 o 70 0 0 1 5o 1 50 2.0 2 70 0 70 1 70 0 0 2.0 2 50 1 50 2 50 2 so 20 2 7o 0 so 2 70 1 70 2.0 2 50 1 so 2 50 2 50 2.0 2 70 1 70 2 70 3 70 2.0 2 70 2 5o 2 50 2 50 2.0 a 70 2 70 4 7o 2 70 2.0 1 70 0 0 1 '10 1 50 2.0 o 10 0 5o 0 70 o 70 2.0 2 0 0 0 1 o 0 o 2.0 a 70 1 70 0 7o 0 0 2.0 2 70 a 2.0 2 5o 1 2.0 2 70 a 2.0 2 50 1 2.0 4 70 3 2.0 2 50 1 EXAMPLE 4 A formulation was prepared as described in Example 1 having the following composition:

Formulation C.Plain finish Component percent OWF Isopropanol a 3.0. Polymer dispersion As indicated.

a On weight of bath. b 6.21% aqueous emulsion of indicated polymer.

This formulation was then applied by padding to a nylon tricot fabric and the results are shown in Table IV It can readily be seen that the polymer of this invention in all instances possesses greater dry-soil resistance than the polymer which is without the scope of the invention.

The foregoing detailed description has been given for clarity of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to exact details shown and described for obvious modifications will occur to one skilled in the art.

1 1 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An oiland water-repellent and dry soil resistant polymer consisting essentially of (a) from about 60 to 95 parts of units derived from monomers having the structure RfCHgCHg where R is a perfiuoroalkyl group of 4 to 14 carbon atoms;

(b) from about 40 to parts of units derived from methyl acrylate or ethyl acrylate monomers, wherein the total weight of the units derived from (a) and (b) present in the polymer is 100 parts; and

(c) from about 0 to 1 part of units derived from monomers selected from CH CRCONHCH OH CH CRCO CH CH OH and mixtures thereof, wherein R is H or CH and wherein the inherent viscosity of said polymer as a 0.5% solution in trichlorotrifiuoroethane at 30 C. is from 0.2 to 3.

2. A polymer according to claim 1 wherein R, in the units defined in part (a) of claim 1 has the formula CF CF (CF wherein n has the numerical values 4, 6, 8, and 12 present in the approximate weight ratio 35/30/18/8/3.

3. A polymer according to claim 1 wherein R in the units CH CRCO-NHCH in part (c) of claim 1 is H.

4. A polymer according to claim 1 wherein R in the units CH =CRCO CH CH OH in part (c) of claim 1 1S CH3.

5. A polymer according to claim 1 wherein the monomer of part (b) of claim 1 is methyl acrylate.

6. A polymer according to claim 5 wherein about 15 to 10 parts of units derived from the methyl acrylate monomer are present.

7. A polymer according to claim 1 consisting essentially of (a) about -90 parts of units derived from References Cited UNITED STATES PATENTS 4/1968 Fasick et al. 260-890 8/1969 Raynolds et al ll7161 JOSEPH L. SCHOFER, Primary Examiner S. M. LEVIN, Assistant Examiner US. Cl. X.R.

260-296 F, 80.75, 80.77, 86.1 E; ll7l26 GR, 138.8 F, 138.8 N, 139.4, 139.5 A, 141, 143 A, 145, 161 UC, 161 UT 

